Commit Graph

157 Commits

Author SHA1 Message Date
Michael S. Tsirkin bc9a839d56 kvm: get/set PV EOI MSR
Support get/set of new PV EOI MSR, for migration.
Add an optional section for MSR value - send it
out in case MSR was changed from the default value (0).

Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>
2012-08-29 10:51:28 -05:00
Peter Maydell f3e1bed8da kvm: Decouple 'GSI routing' from 'kernel irqchip'
Don't assume having an in-kernel irqchip means that GSI
routing is enabled.

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Signed-off-by: Avi Kivity <avi@redhat.com>
2012-08-09 16:16:57 +03:00
Peter Maydell 614e41bc26 kvm: Decouple 'MSI routing via irqfds' from 'kernel irqchip'
Decouple another x86-specific assumption about what irqchips imply.

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Signed-off-by: Avi Kivity <avi@redhat.com>
2012-08-09 16:16:56 +03:00
Peter Maydell cc7e0ddf5a kvm: Decouple 'irqfds usable' from 'kernel irqchip'
Instead of assuming that we can use irqfds if and only if
kvm_irqchip_in_kernel(), add a bool to the KVMState which
indicates this, and is set only on x86 and only if the
irqchip is in the kernel.

The kernel documentation implies that the only thing
you need to use KVM_IRQFD is that KVM_CAP_IRQFD is
advertised, but this seems to be untrue. In particular
the kernel does not (alas) return a sensible error if you
try to set up an irqfd when you haven't created an irqchip.
If it did we could remove all this nonsense and let the
kernel return the error code.

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Acked-by: Jan Kiszka <jan.kiszka@siemens.com>
Signed-off-by: Avi Kivity <avi@redhat.com>
2012-08-09 16:16:56 +03:00
Peter Maydell 1d31f66bbc kvm: Move kvm_allows_irq0_override() to target-i386, fix return type
kvm_allows_irq0_override() is a totally x86 specific concept:
move it to the target-specific source file where it belongs.
This means we need a new header file for the prototype:
kvm_i386.h, in line with the existing kvm_ppc.h.

While we are moving it, fix the return type to be 'bool' rather
than 'int'.

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Signed-off-by: Avi Kivity <avi@redhat.com>
2012-08-09 16:16:55 +03:00
Igor Mammedov dd673288a8 target-i386: move cpu halted decision into x86_cpu_reset
MP initialization protocol differs between cpu families, and for P6 and
onward models it is up to CPU to decide if it will be BSP using this
protocol, so try to model this. However there is no point in implementing
MP initialization protocol in qemu. Thus first CPU is always marked as BSP.

This patch:
 - moves decision to designate BSP from board into cpu, making cpu
self-sufficient in this regard. Later it will allow to cleanup hw/pc.c
and remove cpu_reset and wrappers from there.
 - stores flag that CPU is BSP in IA32_APIC_BASE to model behavior
described in Inted SDM vol 3a part 1 chapter 8.4.1
 - uses MSR_IA32_APICBASE_BSP flag in apic_base for checking if cpu is BSP

patch is based on Jan Kiszka's proposal:
    http://thread.gmane.org/gmane.comp.emulators.qemu/100806

Signed-off-by: Igor Mammedov <imammedo@redhat.com>
Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>
2012-08-01 08:45:06 -05:00
Jan Kiszka 5d62c43a17 apic: Defer interrupt updates to VCPU thread
KVM performs TPR raising asynchronously to QEMU, specifically outside
QEMU's global lock. When an interrupt is injected into the APIC and TPR
is checked to decide if this can be delivered, a stale TPR value may be
used, causing spurious interrupts in the end.

Fix this by deferring apic_update_irq to the context of the target VCPU.
We introduce a new interrupt flag for this, CPU_INTERRUPT_POLL. When it
is set, the VCPU calls apic_poll_irq before checking for further pending
interrupts. To avoid special-casing KVM, we also implement this logic
for TCG mode.

Signed-off-by: Jan Kiszka <jan.kiszka@siemens.com>
Signed-off-by: Avi Kivity <avi@redhat.com>
2012-07-10 11:31:09 +03:00
Liu, Jinsong a75b3e0f64 kvm: expose tsc deadline timer feature to guest
This patch exposes tsc deadline timer feature to guest if
1). in-kernel irqchip is used, and
2). kvm has emulated tsc deadline timer, and
3). user authorize the feature exposing via -cpu or +/- tsc-deadline

Signed-off-by: Liu, Jinsong <jinsong.liu@intel.com>
Reviewed-by: Eduardo Habkost <ehabkost@redhat.com>
Acked-by: Jan Kiszka <jan.kiszka@siemens.com>
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
2012-07-03 17:36:32 -03:00
Andreas Färber 232fc23bed target-i386: Pass X86CPU to do_cpu_{init,sipi}()
Allows to use cpu_reset() in place of cpu_state_reset().

Signed-off-by: Andreas Färber <afaerber@suse.de>
Reviewed-by: Igor Mammedov <imammedo@redhat.com>
2012-06-04 23:00:42 +02:00
Andreas Färber 317ac6201a target-i386: Don't overuse CPUState
Scripted conversion:
  sed -i "s/CPUState/CPUX86State/g" target-i386/*.[hc]
  sed -i "s/#define CPUX86State/#define CPUState/" target-i386/cpu.h

Signed-off-by: Andreas Färber <afaerber@suse.de>
Acked-by: Anthony Liguori <aliguori@us.ibm.com>
2012-03-14 22:20:25 +01:00
Michael S. Tsirkin 7e680753cf kvm: fill in padding to help valgrind
valgrind warns about padding fields which are passed
to vcpu ioctls uninitialized.
This is not an error in practice because kvm ignored padding.
Since the ioctls in question are off data path and
the cost is zero anyway, initialize padding to 0
to suppress these errors.

Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Avi Kivity <avi@redhat.com>
2012-03-07 12:31:48 +02:00
Jan Kiszka d362e757d3 target-i386: Add infrastructure for reporting TPR MMIO accesses
This will allow the APIC core to file a TPR access report. Depending on
the accelerator and kernel irqchip mode, it will either be delivered
right away or queued for later reporting.

In TCG mode, we can restart the triggering instruction and can therefore
forward the event directly. KVM does not allows us to restart, so we
postpone the delivery of events recording in the user space APIC until
the current instruction is completed.

Note that KVM without in-kernel irqchip will report the address after
the instruction that triggered the access.

Signed-off-by: Jan Kiszka <jan.kiszka@siemens.com>
Signed-off-by: Avi Kivity <avi@redhat.com>
2012-02-18 12:15:55 +02:00
Gleb Natapov d1f8663660 kvm: Synchronize cpu state in kvm_arch_stop_on_emulation_error()
Call to kvm_cpu_synchronize_state() is missing.
kvm_arch_stop_on_emulation_error may look at outdated registers here.

Signed-off-by: Gleb Natapov <gleb@redhat.com>
Signed-off-by: Avi Kivity <avi@redhat.com>
Reviewed-by: Jan Kiszka <jan.kiszka@siemens.com>
2012-02-16 18:21:46 +02:00
Jan Kiszka 3d4b26494f kvm: Implement kvm_irqchip_in_kernel like kvm_enabled
To both avoid that kvm_irqchip_in_kernel always has to be paired with
kvm_enabled and that the former ends up in a function call, implement it
like the latter. This means keeping the state in a global variable and
defining kvm_irqchip_in_kernel as a preprocessor macro.

Signed-off-by: Jan Kiszka <jan.kiszka@siemens.com>
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
2012-02-08 15:57:50 -02:00
Jan Kiszka 39d6960aab kvm: Allow to set shadow MMU size
Introduce the KVM-specific machine option kvm_shadow_mem. It allows to
set a custom shadow MMU size for the virtual machine. This is useful for
stress testing e.g.

Only x86 supports this for now, but it is in principle a generic
concept for all targets with shadow MMUs.

Signed-off-by: Jan Kiszka <jan.kiszka@siemens.com>
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
2012-02-08 15:57:50 -02:00
Jan Kiszka 680c1c6fd7 kvm: x86: Add user space part for in-kernel APIC
This introduces the alternative APIC device which makes use of KVM's
in-kernel device model. External NMI injection via LINT1 is emulated by
checking the current state of the in-kernel APIC, only injecting a NMI
into the VCPU if LINT1 is unmasked and configured to DM_NMI.

MSI is not yet supported, so we disable this when the in-kernel model is
in use.

CC: Lai Jiangshan <laijs@cn.fujitsu.com>
Signed-off-by: Jan Kiszka <jan.kiszka@siemens.com>
2012-01-19 12:14:42 +01:00
Jan Kiszka 84b058d7df kvm: Introduce core services for in-kernel irqchip support
Add the basic infrastructure to active in-kernel irqchip support, inject
interrupts into these models, and maintain IRQ routes.

Routing is optional and depends on the host arch supporting
KVM_CAP_IRQ_ROUTING. When it's not available on x86, we looe the HPET as
we can't route GSI0 to IOAPIC pin 2.

In-kernel irqchip support will once be controlled by the machine
property 'kernel_irqchip', but this is not yet wired up.

Signed-off-by: Jan Kiszka <jan.kiszka@siemens.com>
2012-01-19 12:14:42 +01:00
Vadim Rozenfeld eab70139a6 hyper-v: initialize Hyper-V CPUID leaves.
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
2012-01-19 08:33:12 -02:00
Anthony Liguori f3c6a169a3 Merge remote-tracking branch 'qemu-kvm/memory/page_desc' into staging
* qemu-kvm/memory/page_desc: (22 commits)
  Remove cpu_get_physical_page_desc()
  sparc: avoid cpu_get_physical_page_desc()
  virtio-balloon: avoid cpu_get_physical_page_desc()
  vhost: avoid cpu_get_physical_page_desc()
  kvm: avoid cpu_get_physical_page_desc()
  memory: remove CPUPhysMemoryClient
  xen: convert to MemoryListener API
  memory: temporarily add memory_region_get_ram_addr()
  xen, vga: add API for registering the framebuffer
  vhost: convert to MemoryListener API
  kvm: convert to MemoryListener API
  kvm: switch kvm slots to use host virtual address instead of ram_addr_t
  memory: add API for observing updates to the physical memory map
  memory: replace cpu_physical_sync_dirty_bitmap() with a memory API
  framebuffer: drop use of cpu_physical_sync_dirty_bitmap()
  loader: remove calls to cpu_get_physical_page_desc()
  framebuffer: drop use of cpu_get_physical_page_desc()
  memory: introduce memory_region_find()
  memory: add memory_region_is_logging()
  memory: add memory_region_is_rom()
  ...
2012-01-03 14:39:05 -06:00
Jan Kiszka cce47516cd kvm: x86: Drop redundant apic base and tpr update from kvm_get_sregs
The latter was already commented out, the former is redundant as well.
We always get the latest changes after return from the guest via
kvm_arch_post_run.

Signed-off-by: Jan Kiszka <jan.kiszka@siemens.com>
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
2011-12-22 14:53:01 -02:00
Jan Kiszka fabacc0f79 kvm: x86: Avoid runtime allocation of xsave buffer
Keep a per-VCPU xsave buffer for kvm_put/get_xsave instead of
continuously allocating and freeing it on state sync.

Signed-off-by: Jan Kiszka <jan.kiszka@siemens.com>
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
2011-12-22 14:53:01 -02:00
Jan Kiszka 6b42494b21 kvm: x86: Use symbols for all xsave field
Field 0 (FCW+FSW) and 1 (FTW+FOP) were hard-coded so far.

Signed-off-by: Jan Kiszka <jan.kiszka@siemens.com>
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
2011-12-22 14:53:00 -02:00
Avi Kivity 9f213ed92c kvm: switch kvm slots to use host virtual address instead of ram_addr_t
This simplifies a later switch to the memory API in slot management.

Signed-off-by: Avi Kivity <avi@redhat.com>
2011-12-20 14:14:07 +02:00
Vagrant Cascadian 126197214e Fix typo: runnning -> running
One n too many for running, need we say more.

Signed-Off-By: Vagrant Cascadian <vagrant@freegeek.org>

Signed-off-by: Stefan Hajnoczi <stefanha@linux.vnet.ibm.com>
2011-11-17 12:57:41 +00:00
Avi Kivity 21e87c4625 i386: wire up MSR_IA32_MISC_ENABLE
It's needed for its default value - bit 0 specifies that "rep movs" is
good enough for memcpy, and Linux may use a slower memcpu if it is not set,
depending on cpu family/model.

Signed-off-by: Avi Kivity <avi@redhat.com>
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
2011-10-24 21:33:32 -02:00
Liu, Jinsong aa82ba549a kvm: support TSC deadline MSR with subsection
KVM add emulation of lapic tsc deadline timer for guest.
This patch is co-operation work at qemu side.

Use subsections to save/restore the field (mtosatti).

Signed-off-by: Liu, Jinsong <jinsong.liu@intel.com>
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
2011-10-24 21:29:07 -02:00
Marcelo Tosatti 38d2c27ea6 Revert "kvm: support TSC deadline MSR"
This reverts commit bfc2455ddb.
New patch with subsections will follow.

Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
2011-10-24 21:27:16 -02:00
Liu, Jinsong bfc2455ddb kvm: support TSC deadline MSR
KVM add emulation of lapic tsc deadline timer for guest.
This patch is co-operation work at qemu side.

Signed-off-by: Liu, Jinsong <jinsong.liu@intel.com>
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
2011-10-03 13:53:14 -03:00
Luiz Capitulino 1354869c38 Drop the vm_running global variable
Use runstate_is_running() instead, which is introduced by this commit.

Signed-off-by: Luiz Capitulino <lcapitulino@redhat.com>
2011-09-15 16:39:32 -03:00
Luiz Capitulino 1dfb4dd993 Replace the VMSTOP macros with a proper state type
Today, when notifying a VM state change with vm_state_notify(),
we pass a VMSTOP macro as the 'reason' argument. This is not ideal
because the VMSTOP macros tell why qemu stopped and not exactly
what the current VM state is.

One example to demonstrate this problem is that vm_start() calls
vm_state_notify() with reason=0, which turns out to be VMSTOP_USER.

This commit fixes that by replacing the VMSTOP macros with a proper
state type called RunState.

Signed-off-by: Luiz Capitulino <lcapitulino@redhat.com>
2011-09-15 16:39:32 -03:00
Blue Swirl 6115c0a82d kvm: remove unnecessary assignments
Avoid these warnings from clang analyzer:
/src/qemu/target-i386/kvm.c:772:5: warning: Value stored to 'cwd' is never read
    cwd = swd = twd = 0;
/src/qemu/target-i386/kvm.c:772:11: warning: Although the value stored to 'swd' is used in the enclosing expression, the value is never actually read from 'swd'
    cwd = swd = twd = 0;

Signed-off-by: Blue Swirl <blauwirbel@gmail.com>
2011-09-10 14:50:00 +00:00
Stefan Weil 541dc0d47f Use new macro QEMU_PACKED for packed structures
Most changes were made using these commands:

git grep -la '__attribute__((packed))'|xargs perl -pi -e 's/__attribute__\(\(packed\)\)/QEMU_PACKED/'
git grep -la '__attribute__ ((packed))'|xargs perl -pi -e 's/__attribute__ \(\(packed\)\)/QEMU_PACKED/'
git grep -la '__attribute__((__packed__))'|xargs perl -pi -e 's/__attribute__\(\(__packed__\)\)/QEMU_PACKED/'
git grep -la '__attribute__ ((__packed__))'|xargs perl -pi -e 's/__attribute__ \(\(__packed__\)\)/QEMU_PACKED/'
git grep -la '__attribute((packed))'|xargs perl -pi -e 's/__attribute\(\(packed\)\)/QEMU_PACKED/'

Whitespace in linux-user/syscall_defs.h was fixed manually
to avoid warnings from scripts/checkpatch.pl.

Manual changes were also applied to hw/pc.c.

I did not fix indentation with tabs in block/vvfat.c.
The patch will show 4 errors with scripts/checkpatch.pl.

Signed-off-by: Stefan Weil <weil@mail.berlios.de>
Signed-off-by: Blue Swirl <blauwirbel@gmail.com>
2011-09-03 10:45:59 +00:00
Jan Kiszka fdc9c41a5a Fix up some style nits of last uq/master merge
Signed-off-by: Jan Kiszka <jan.kiszka@siemens.com>
Signed-off-by: Stefan Hajnoczi <stefanha@linux.vnet.ibm.com>
2011-08-25 09:21:35 +01:00
Anthony Liguori 7267c0947d Use glib memory allocation and free functions
qemu_malloc/qemu_free no longer exist after this commit.

Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>
2011-08-20 23:01:08 -05:00
Marcelo Tosatti ac363c9042 Remove #ifdef KVM_CAP_TSC_CONTROL
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
2011-08-05 12:10:55 -03:00
Joerg Roedel e7429073ed qemu-x86: Set tsc_khz in kvm when supported
Make use of the KVM_TSC_CONTROL feature if available.

Signed-off-by: Joerg Roedel <joerg.roedel@amd.com>
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
2011-08-05 12:04:27 -03:00
Andre Przywara 31e8c69697 KVM: Fix XSAVE feature bit enumeration
When iterating through the XSAVE feature enumeration CPUID leaf (0xD)
we should not stop at the first zero EAX, but instead keep scanning
since there are gaps in the enumeration (ECX=1 for instance).
This fixes the proper usage of AVX in KVM guests.

Signed-off-by: Andre Przywara <andre.przywara@amd.com>
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
2011-06-20 15:26:21 -03:00
Jan Kiszka ba9bc59e1f kvm: x86: Pass KVMState to kvm_arch_get_supported_cpuid
kvm_arch_get_supported_cpuid checks for global cpuid restrictions, it
does not require any CPUState reference. Changing its interface allows
to call it before any VCPU is initialized.

CC: Eduardo Habkost <ehabkost@redhat.com>
Signed-off-by: Jan Kiszka <jan.kiszka@siemens.com>
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
2011-06-20 15:24:00 -03:00
Jan Kiszka e56ff191b6 kvm: x86: Drop KVM_CAP build dependencies
No longer needed with accompanied kernel headers.

Signed-off-by: Jan Kiszka <jan.kiszka@siemens.com>
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
2011-06-20 15:19:54 -03:00
Jan Kiszka 5802e066eb kvm: Drop CONFIG_KVM_PARA
The kvm_para.h header is now always available.

Signed-off-by: Jan Kiszka <jan.kiszka@siemens.com>
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
2011-06-20 15:16:45 -03:00
Jan Kiszka 42cc8fa620 kvm: x86: Save/restore FPU OP, IP and DP
These FPU states are properly maintained by KVM but not yet by TCG. So
far we unconditionally set them to 0 in the guest which may cause
state corruptions, though not with modern guests.

To avoid breaking backward migration, use a conditional subsection that
is only written if any of the three fields is non-zero. The guest's
FNINIT clears them frequently, and cleared IA32_MISC_ENABLE MSR[2]
reduces the probability of non-zero values further so that this
subsection is not expected to restrict migration in any common scenario.

Signed-off-by: Jan Kiszka <jan.kiszka@siemens.com>
Signed-off-by: Avi Kivity <avi@redhat.com>
2011-06-19 15:57:56 +03:00
brillywu@viatech.com.cn b3baa152aa kvm: Add CPUID support for VIA CPU
When KVM is running on VIA CPU with host cpu's model, the
feautures of VIA CPU will be passed into kvm guest by calling
the CPUID instruction for Centaur.

Signed-off-by: BrillyWu<brillywu@viatech.com.cn>
Signed-off-by: KaryJin<karyjin@viatech.com.cn>
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
2011-06-14 09:34:35 -05:00
Paolo Bonzini 4a043713b3 kvm: use qemu_free consistently
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
2011-05-02 09:51:59 -03:00
Glauber Costa 0c31b744f6 kvm: use kernel-provided para_features instead of statically coming up with new capabilities
Use the features provided by KVM_GET_SUPPORTED_CPUID directly to
mask out features from guest-visible cpuid.

The old get_para_features() mechanism is kept for older kernels that do not implement it.

Signed-off-by: Glauber Costa <glommer@redhat.com>
Signed-off-by: Avi Kivity <avi@redhat.com>
2011-05-02 08:24:42 -03:00
Jan Kiszka f2574737f6 kvm: x86: Push kvm_arch_debug to kvm_arch_handle_exit
There are no generic bits remaining in the handling of KVM_EXIT_DEBUG.
So push its logic completely into arch hands, i.e. only x86 so far.

Signed-off-by: Jan Kiszka <jan.kiszka@siemens.com>
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
2011-03-16 17:11:06 -03:00
Jan Kiszka 2a4dac8350 kvm: x86: Reorder functions in kvm.c
Required for next patch which will access guest debug services from
kvm_arch_handle_exit. No functional changes.

Signed-off-by: Jan Kiszka <jan.kiszka@siemens.com>
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
2011-03-16 17:11:06 -03:00
Jan Kiszka bb4ea39329 kvm: Align kvm_arch_handle_exit to kvm_cpu_exec changes
Make the return code of kvm_arch_handle_exit directly usable for
kvm_cpu_exec. This is straightforward for x86 and ppc, just s390
would require more work. Avoid this for now by pushing the return code
translation logic into s390's kvm_arch_handle_exit.

Signed-off-by: Jan Kiszka <jan.kiszka@siemens.com>
CC: Alexander Graf <agraf@suse.de>
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
2011-03-16 17:11:06 -03:00
Jan Kiszka 0c03266a96 kvm: x86: Synchronize PAT MSR with the kernel
Signed-off-by: Jan Kiszka <jan.kiszka@siemens.com>
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
2011-03-16 17:11:05 -03:00
Jan Kiszka 4601f7b04c kvm: x86: Do not leave halt if interrupts are disabled
When an external interrupt is pending but IF is cleared, we must not
leave the halt state prematurely.

Signed-off-by: Jan Kiszka <jan.kiszka@siemens.com>
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
2011-03-16 17:11:05 -03:00
Huang Ying 3c85e74fbf KVM, MCE, unpoison memory address across reboot
In Linux kernel HWPoison processing implementation, the virtual
address in processes mapping the error physical memory page is marked
as HWPoison.  So that, the further accessing to the virtual
address will kill corresponding processes with SIGBUS.

If the error physical memory page is used by a KVM guest, the SIGBUS
will be sent to QEMU, and QEMU will simulate a MCE to report that
memory error to the guest OS.  If the guest OS can not recover from
the error (for example, the page is accessed by kernel code), guest OS
will reboot the system.  But because the underlying host virtual
address backing the guest physical memory is still poisoned, if the
guest system accesses the corresponding guest physical memory even
after rebooting, the SIGBUS will still be sent to QEMU and MCE will be
simulated.  That is, guest system can not recover via rebooting.

In fact, across rebooting, the contents of guest physical memory page
need not to be kept.  We can allocate a new host physical page to
back the corresponding guest physical address.

This patch fixes this issue in QEMU-KVM via calling qemu_ram_remap()
to clear the corresponding page table entry, so that make it possible
to allocate a new page to recover the issue.

[ Jan: rebasing and tiny cleanups]

Signed-off-by: Huang Ying <ying.huang@intel.com>
Signed-off-by: Jan Kiszka <jan.kiszka@siemens.com>
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
2011-03-15 01:19:06 -03:00